The present invention relates continuous mining apparatus, and particularly to a means for controlling the dust produced in a continuous mining operation.
In a continuous mining operation considerable dust is produced as the cutting head of the miner cuts coal away from the cutting face of the mine. Obviously, some means must be provided for proper dust control in the cutting areas of continuous mining apparatus. The dust level present in the air surrounding the continuous mining apparatus must be controlled from both a health standpoint and safety standpoint to prevent explosions.
In U.S. Pat. No. 4,315,658 there is shown continuous mining apparatus that includes a curtain means for guiding the airborne dust generated by the cutting head toward a passage. The passage directs the dust-laden air away from the ventilation air that is supplied to the cutting face of the equipment. Means that includes both fans and hydraulic nozzles are provided for inducing an air flow in the passage means. While the '658 patent shows means for removing the dust-laden air from the vicinity of the cutting head, it does not disclose any means for removing the dust from the air so that the air can be recirculated within the mine. Instead, the '658 patent merely shows discharging the dust-laden air to the rear of the mining apparatus.
In U.S. Pat. No. 3,904,246 there is shown a rotary cutting head for use in a continuous mining apparatus that incorporates air flow inducing devices mounted in the cutting head. In particular, the '246 patent shows air flow guide means in the cutting head with fluid nozzles used for inducing an air flow into the guide means. Again, the '246 patent does not specifically describe any means for removing the dust from the air. The '246 patent does mention the use of nozzles for dispersing a dust suppression fluid in the dust-laden air.
Another continuous miner is shown in U.S. Pat. No. 4,037,875 that incorporates fans for removing the dust-laden air from the vicinity of the cutting heads. The '875 patent discloses the use of nozzles for spraying a liquid into the confined area adjacent the face of the mine but does not specifically disclose any means for removing the dust from the air that is exhausted by the fans that are incorporated in the mining apparatus.
Three Technology News bulletins of the Bureau of Mines, United States Department of the Interior, No. 117, Nov. 1981; No. 322, Jan. 1989; and No. 337, May 1989, all describe high pressure scrubbers for use with continuous underground mining equipment. All of these scrubbers depend on the high pressure water nozzles for producing an air flow through the scrubber and removing the dust. This results in a large consumption of water in relation to the air flow produced and creates a water disposal problem. In addition, all of the systems utilize demisters for removing the water and entrained dust from the air before it is returned to the mine atmosphere. The demisters are screen-type filters that clog after a few hours of use and require frequent cleaning.
From the above description of the prior art patents, it is seen that they all recognize the need to remove the dust-laden air from the vicinity of the cutting head in a continuous mining apparatus but do not provide an efficient means for removing such dust from the air. While the patents do disclose the use of fluid nozzles either for inducing the flow in the air removal means or for suppressing the dust, they do not describe specific means for removing the dust from the air so that the air may be recirculated in the mining operation.